Commit 99c787cf authored Jul 24, 2020 by Li Guifu Committed by Jaegeuk Kim Jul 23, 2020

f2fs: fix use-after-free issue



During umount, f2fs_put_super() unregisters procfs entries after
f2fs_destroy_segment_manager(), it may cause use-after-free
issue when umount races with procfs accessing, fix it by relocating
f2fs_unregister_sysfs().

[Chao Yu: change commit title/message a bit]

Signed-off-by: Li Guifu <bluce.liguifu@huawei.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

parent 68e79baf

fs/f2fs/super.c

+3 −2

Original line number	Diff line number	Diff line
		@@ -1175,6 +1175,9 @@ static void f2fs_put_super(struct super_block *sb)
		int i;
		bool dropped;

		/* unregister procfs/sysfs entries in advance to avoid race case */
		f2fs_unregister_sysfs(sbi);

		f2fs_quota_off_umount(sb);

		/* prevent remaining shrinker jobs */
		@@ -1240,8 +1243,6 @@ static void f2fs_put_super(struct super_block *sb)

		kvfree(sbi->ckpt);

		f2fs_unregister_sysfs(sbi);

		sb->s_fs_info = NULL;
		if (sbi->s_chksum_driver)
		crypto_free_shash(sbi->s_chksum_driver);

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